Old Glass, New Skies: Mapping a Century of Cosmic Change

The article explains how astronomy blends modern time-domain surveys with century-old glass plates to trace cosmic changes over long timescales. By digitizing archives like Harvard’s DASCH and comparing them with new data from the Vera C. Rubin Observatory, researchers build a century-long view of variability—from supernovae and active galactic nuclei to variable stars—creating a “movie” of the sky while tackling challenges in data calibration and plate preservation.